Summary: <tt> is deprecated in HTML5 and should be avoided: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/tt Replace the hardcoded <tt> elements with semantically more appropriate alternatives and update our CSS accordingly. Note: This change does not handle/affect <tt> elements created by Phorge in a Remarkup context (`tt.remarkup-monospaced`). Test Plan: * Go to http://phorge.localhost/uiexample/view/PHUITimelineExample/ and look at the top box * Go to http://phorge.localhost/config/issue/ and open an issue which shows a command in its description (e.g. "Daemons Are Not Running") Reviewers: O1 Blessed Committers, mainframe98 Reviewed By: O1 Blessed Committers, mainframe98 Subscribers: mainframe98, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno Differential Revision: https://we.phorge.it/D26671